1. Field of the Invention
The present invention relates generally to a variable valve timing system and more specifically to a variable valve timing system which includes an arrangement for automatically maintaining the valve clearance essentially zero during all modes of operation.
2. Description of the Prior Art
In a previously proposed arrangement (shown in FIG. 1) a rotatable cam 1 operatively contacts one end of a rocker arm 3 which is eccentrically journalled on a rocker shaft 5. The other end of the rocker arm 3 is in contact with a swingable cam 4 which is journalled on a shaft 7. As shown the swingable cam 4 is adapted to operatively abut the head section of a popper valve 8.
However, this arrangement suffers from the drawback that, as the cam is mounted on the shaft 7, the clearance between the cam and the head section of the valve 8 cannot be readily adjusted and a noise generating clearance must be provided therebetween.
For a full and complete disclosure of the above described arrangement, reference is made to U.S. patent application Ser. No. 138,792 filed on Apr. 8, 1980 in the name of Shunichi AOYAMA.